This invention relates to covers and more particularly to thermal covers for backflow prevention assemblies to prevent freeze-up.
Ever since the arrival of the automatic lawn sprinkler systems, the possibility of cross contamination of public water supplies has caused great concern. To protect public water supplies from possible cross contamination by sprinkler systems, backflow prevention assemblies were introduced. When installed correctly these devices prevent cross contamination from back siphonage with a pressure vacuum breaker (PVB) and back pressure with a reduced pressure principle assembly (RP).
Typically, to allow these backflow prevention assemblies to function properly and meet manufacturer""s specifications, these devices are installed outside and above ground, making them highly susceptible to freezing temperatures. In northern climates, sprinkler systems are either blown out with compressed air or drained to avoid freeze damage. In moderately temperate climates with little or no ground frost, systems may be used year ""round or may be left unused during the dormant season, assuming some protection is provided to the above ground water-carrying components.
Protecting the backflow prevention assemblies against freezing is paramount due to the relatively high cost of replacement parts and their tendency to xe2x80x9ccollectxe2x80x9d cold air faster than their above-ground counterparts. Due to the unpredictability of spring and fall weather, the degree that these backflow prevention assemblies are prone to freeze damage and since many property owners and/or managers desire to water well into the transitional periods of weather, a simple method of protecting against such freeze damage is desirable.
Some previous attempts have been made to provide covers for backflow prevention assemblies. Barthuly U.S. Pat. No. 6,206,030 describes a cover for water backflow prevention that covers the backflow prevention assembly and anchors to the ground. Pawar et al. U.S. Pat. No. Des. 349,754 discloses a design for a cover for water backflow prevention that fits over the backflow prevention assembly but does not close the assembly along the bottom opening.
A first embodiment of the present invention disclosed has a thermal cover with a thermally lined top wall, opposed thermally lined side walls, fixedly closed end walls, and a variable shaped bottom opening with the side walls flexing outward to allow the cover to spread apart and fit down over the backflow prevention assembly. An adjustable bottom closure is closed and fits around at least one pipe extending through the bottom of the cover to close the bottom opening. A second embodiment is similar to the first but further has variable shaped openings along both opposed end walls to allow pipes connected to the backflow prevention assembly to extend through the ends as well as through the bottom. These end openings are selectively opened and closed with adjustable end closures. This embodiment will open up to a flat blanket like configuration. Velcro-type co-acting first and second fastening members are disclosed as an adjustable closure for both the bottom and sides. A thermal cover according to the present invention is easy to install and is adjustable to fit most all residential/light commercial backflow prevention assemblies. The disclosed thermal cover protects backflow prevention assemblies in case of a short overnight hard freeze, or during extended periods of ambient air temperatures hovering at or below the freezing mark.